CNN is currently running this story about a crash survivor burying another survivor in sand to prevent hypothermia. It seems to me this would be more likely to cause a further loss of body heat. Any opinions?


"A pilot dragged his passenger to safety and buried him neck-deep in sand to protect him from hypothermia Sunday night after their helicopter crashed in crocodile-infested mudflats in Australia's Northern Territory.
............................

Finding his friend seriously hurt, the pilot dragged him back to shore, away from the crocodiles -- and buried him in sand up to his neck to prevent him from freezing to death."

http://www.cnn.com/2009/WORLD/asiapcf/06/22/australia.chopper.crash/index.html

I don't know about the hypothermia angle but I think I wouldn't like being buried neck deep in croc territory!

That's what I was thinking.

I searched for more information and found a little more detail in an Australian online news site. It turns out that the two were rescued after only 90 minutes, so there was not much time to test the effect of being buried on hypothermia. One rescuer seemed to think the pilot took the proper action however.

http://www.theaustralian.news.com.au/story/0,25197,25674772-5013404,00.html

If the sand is dry, in the daytime just a few inches below the surface it will be much cooler than the daily maximum at the surface. Below about a foot, the sand will be at about the average daily surface temperature.

In the autumn, the temperature of the sand will increase slightly as depth increases, but this effect is very small in the upper few feet. Geothermal heat flux is negligible.

All this is based on the physics of conduction in solids with a daily or annual wave at the surface. All you need to solve the equation is the mean and amplitude at the surface,the period of the wave (one day or one year) and the thermal diffusivity of the sand. Dry sand has a very low diffusivity compared to most soils, so the depth at which the surface cycle peters out is relatively shallow.

While I didn't read the article, I wonder if he was misquoted and meant hyperthermia vice hypothermia.

Bill

Well, it is winter down under this time of year......

Fortunately I keep this exact information printed on the survival cards I stash in my kits. Knowledge is power!

I apologize to everyone for the geeky response I gave above. I could have given the basic result/advice without the physical basis, but I work with these equations regularly as an earth scientist. It's standard procedure to back up assertions so that the reader can arrive at the same results if they doubt me.

If you've been on a beach with burning hot sand, you know that it's much cooler just and inch or two underneath.

No need to apologize, I thought your answer rocked!

-Blast